The purpose presentation is to demonstrate the use of a standing microwave technique for the determination of absolute thickness and remaining wall in products which are fabricated of fiber reinforced plastics (FRP). These products include primarily piping systems and tanks, but include laminates used as the exposed surfaces in components which are made of other materials. The goal of this inspection is to detect and characterize wall thickness of pipes and tanks, given access to only the outside surface. This technique is intended to be used to detect thickness and, especially variations in thickness, caused by mechanical damage (such as erosion) or chemical attack. This presentation highlights the fact that the standing microwave technique described herein has the ability to detect small changes in wall thickness which are often associated with the very earliest stages of chemical attack (blistering). This inspection technique has been developed to be applicable to inspection whether the inspected vessel is in service or out of service, empty or filled with its associated process fluid.